Project Summary Out of over 380,000 brain surgeries performed in the USA every year, at least 20% are to remove lesions located inside or adjacent to the brain?s ventricles, i.e., cavities filled with clear fluid. Using endoscopes, neurosurgeons can navigate their instruments through the ventricles to reach these lesions with less damage to healthy brain tissue than occurs in open surgery. Current endoscopes, however, are restricted by three main factors which limit their use to about 5% of the potential cases (1% of all brain surgeries). First, endoscopes have tools emerging parallel to the working shaft, precluding many of the two-handed surgical techniques of open surgery that are used to dissect tissue and stop bleeding. Second, most neurosurgeons use straight rigid endoscopes that cannot negotiate around corners without causing significant brain retraction injury. Third, there is a risk of leaving behind significant residual tumors and also injuring critical neurovascular structures that are not directly in the line of sight. The first two problems can be solved by providing two dexterous arms at the tip of endoscope and by enabling easily controllable steerability for navigating around corners. The third issue can be addressed by intraoperative MR imaging, with the added benefit of real-time imaging of the target lesion throughout the operation. Currently, however, intraoperative MRI is limited to open surgery and allows only intermittent imaging due to MR-incompatibility of standard surgical instruments as well as the difficult ergonomics of operating inside a scanner. The project goal is to create robotic endoscopes for use inside an MR scanner. These surgeon- controlled instruments will enable intuitive steering through the ventricles to the site of a lesion. There, two tip- mounted dextrous arms can be deployed for bimanual lesion resection under combined endoscopic and MR visualization. It is anticipated that these systems will enable endoscopic resection of 50% of lesions inside and adjacent to the ventricles (10% of all intracranial lesions) while also improving the safety and efficacy of current endoscopic procedures ? resulting in a 10-fold increase in the number of brain surgeries that can be treated endoscopically. Aim I will create a straight MRI-compatible bimanual neuroendoscope with two dexterous arms comprised of telescoping elastic tubes. Aim II will offer a longer curvilinear surgical trajectory to deeper ventricular and periventricular lesions by integrating a telescoping tendon-drive technology for endoscope steerability with the tip-mounted arms of Aim 1. Both systems will be evaluated and refined through a series of phantom and animal studies. The project leaders are experts in neuroendoscopic surgery, MRI-compatible technologies and medical robot design.